Angiogenesis in Distraction Osteogenesis / 대한정형외과학회잡지

PURPOSE: Distraction osteogenesis is now a standard method for bone lengthening. However, little is known about the exact mechanism of new bone formation. This study was undertaken to investigate the temporal and spatial changes of angiogenesis during the periods of distraction osteogenesis; the three-dimensional microarchitecture of newly formed vessels and their origin; and the role of angiogenesis with reference to mineralization. MATERIALS AND METHODS: Sprague-Dawley rat's tibia was osteotomized subperiosteally and was distracted at a rate of 0.5 mm per day for two weeks after one week of latency period. Vascular corrosion casting using Mercox was done on the hindlimbs before osteotomy, and at the 1st, 2nd, 3rd, 4th, and 6th weeks postoperatively. Replicated microvascular structures and their distribution patterns at the distraction site and adjacent parent bone were observed temporally and spatially under scanning electron microscope. These findings were compared with radiographical and histological observations. RESULTS: 1. At postoperative first week and second week, proliferation of periosteal vessels were more pronounced than that of endosteal vessels, which corresponded to the early new bone formation in subperiosteal area on histologic sections. 2. At postoperative third week, arterial branches from the medulla of parent bone entered into the distraction gap. Multiple longitudinal vascular branches sprouted out from the newly formed vascular network, and ran towards the interzone. 3. At postoperative fourth week, there was vascular proliferation in the periosteal side of interzone, from which branches arose towards the parent bone. 4. At postoperative sixth week, vascular networks of both sides connected to each other, and few angiogenetic findings were observed. CONCLUSIONS: In distraction osteogenesis, angiogenesis occurred actively during the distraction period and then gradually decreased with time. Taken together with radiographical and histological findings, close temporal and spatial relationship between the angiogenesis and new bone formation at the distraction site was revealed.

Effects of cis - Platin on the Type I Collagen of the Osteoid in the Metaphysis of Rat Tibia / 대한정형외과학회잡지

The present study has been undertaken to pursue the cytotoxic effects of cis-Platin on the osteoid formation in metaphysis of rat tibia. By using the immunohistological staining method for type I collagen in rat tibial osteoid, the author detected the deposition of type I collagen, which is the collagenous constituent of endochondral osteoid, after administration of cis-Platin in experimental animals. For the immunological reactions of type I collagen, we used the rabbit anti-rat collagen type I polyclonal antibody as primary antibody and biotinylated goat anti-rabbit IgG as secondary antibody. The distributions of immunohistological reactions in the each of metaphyseal osteoids were analyzed with an image analyzer, and we studied the variances of type I collagens by statistical probabilities. In 12 hours after cis-Platin injection, immunoreactive area in the osteoid of metaphysis was distinctly decreased. Immunoreactive area of type I collagen in osteoids of 1 day and 3 days group metaphysis was increased more than that of 12 hours group and the type I collagen in the metaphysis showed weak immunoreactions of type I collagens with an image analyzer. In the osteoids of 7 days group after cis-Platin injection, the immunoreactive area was similar to that of control group. It is consequently suggested that cis-Platin would induce the decrease of type I collagen in the osteoid. But the type I collagen in tibial osteoid shows the increase from a few days after cis-Platin injection.